In one embodiment, an AC-DC power converter can include: (i) a rectifier bridge and filter to convert an external AC voltage to a DC input voltage; (ii) a first energy storage element to store energy from the DC input voltage via a first current through a first conductive path when in a first operation mode; (iii) a second energy storage element configured to store energy from a second DC voltage via a second current through a second conductive path when in the first operation mode; (iv) a transistor configured to share the first and second conductive paths; (v) the first energy storage element releasing energy to a third energy storage element and a load through a third conductive path when in a second operation mode; and (vi) the second energy storage element releasing energy to the load through a fourth conductive path during the second operation mode.
Legal claims defining the scope of protection, as filed with the USPTO.
1. An AC-DC power converter, comprising: a) a rectifier bridge and filter configured to convert an external AC voltage to a sine half-wave DC input voltage; b) a first energy storage element configured to store energy from said sine half-wave DC input voltage via a first current through a first conductive path during a first operation mode, wherein said first current rises during said first operation mode; c) a second energy storage element configured to store energy from a second DC voltage via a second current through a second conductive path during said first operation mode, wherein said second current rises during said first operation mode; d) a transistor configured to share said first and second conductive paths; e) said first energy storage element being configured to release energy to a third energy storage element and a load through a third conductive path during a second operation mode, wherein said third energy storage element is configured to generate said second DC voltage, and wherein said first current declines during said second operation mode; and f) said second energy storage element being configured to release energy to said load through a fourth conductive path during said second operation mode, wherein a peak value of said first current is configured to vary along with said sine half-wave DC input voltage, and wherein an output of said AC-DC converter is configured to be substantially constant.
2. The AC-DC power converter of claim 1 , wherein: a) said first energy storage element comprises a first inductor; b) said second energy storage element comprises a second inductor; and c) said third energy storage element comprises a capacitor.
3. The AC-DC power converter of claim 1 , wherein: a) said transistor is on during said first operation mode; and b) said transistor is off during said second operation mode.
4. The AC-DC power converter of claim 1 , wherein a first power stage circuit comprises said first and third energy storage elements, and said first and third conductive paths.
5. The AC-DC power converter of claim 1 , wherein a second power stage circuit comprises said second energy storage element, and said second and fourth conductive paths.
6. The AC-DC power converter of claim 1 , configured to provide a substantially constant output current to drive a light-emitting diode (LED) load.
7. The AC-DC power converter of claim 1 , wherein said first conductive path is formed during each switching cycle of said AC-DC power converter.
8. The AC-DC power converter of claim 1 , wherein said first and second operation modes occur during a switching cycle of said AC-DC power converter.
9. The AC-DC power converter of claim 1 , wherein said second energy storage element comprises a transformer.
10. The AC-DC power converter of claim 1 , wherein said load is configured to receive energy from said sine half-wave DC input voltage through said first conductive path in said first operation mode.
11. The AC-DC power converter of claim 10 , wherein said load is configured to receive energy from said second DC voltage through said second conductive path.
12. The AC-DC power converter of claim 1 , further comprising a control and driving circuit configured to receive peak current signals of said first and second currents, and to generate a driving signal to drive said transistor.
13. The AC-DC power converter of claim 12 , wherein said control and driving circuit is configured to regulate an on time of said transistor in accordance with said peak current signals of said first and second currents and current decreasing time signals of said first and second currents from a peak current to zero.
14. The AC-DC power converter of claim 12 , wherein said first and second currents are operated at a boundary conduction mode (BCM).
15. A method of controlling an AC-DC power converter, the method comprising: a) converting, by a rectifier bridge and filter, an external AC voltage to a sine half-wave DC input voltage; b) storing energy from said sine half-wave DC input voltage in a first energy storage element via a first current through a first conductive path during a first operation mode, wherein said first current rises during said first operation mode; c) storing energy from a second DC voltage in a second energy storage element via a second current through a second conductive path during said first operation mode, wherein said second current rises during said first operation mode, and wherein said first and second conductive paths share a transistor; d) releasing energy from said first energy storage element to a third energy storage element and a load through a third conductive path during a second operation mode, wherein said third energy storage element generates said second DC voltage, and wherein said first current declines during said second operation mode; and e) releasing energy from said second energy storage element to said load through a fourth conductive path during said second operation mode, wherein a peak value of said first current varies along with said sine half-wave DC input voltage, and maintaining an output of said AC-DC converter as substantially constant.
16. The method of claim 15 , wherein said second energy storage element comprises a transformer.
17. The method of claim 15 , wherein said first and second operation modes occur during a switching cycle of said AC-DC power converter.
18. The method of claim 17 , further comprising: a) receiving energy from said sine half-wave DC input voltage in said load through said first conductive path during said first operation mode; and b) receiving energy from said second DC voltage in said load through said second conductive path.
19. The method of claim 17 , further comprising: a) receiving, by a control and driving circuit, peak current signals of said first and second currents; and b) generating a driving signal to drive said transistor.
20. The method of claim 17 , further comprising: a) turning on said transistor during said first operation mode; and b) turning off said transistor during said second operation mode.
21. The method of claim 17 , wherein said AC-DC power converter comprises a first power stage circuit having said first and third energy storage elements, and said first and third conductive paths.
22. The method of claim 17 , wherein said AC-DC power converter comprises a second power stage circuit having said second energy storage element, and said second and fourth conductive paths.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
August 12, 2015
December 27, 2016
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